A prescribed sequence of washing — hands, mouth, nose, face, arms, head, and feet — that a Muslim performs before the five daily prayers, to be in a state of purity. It's why mosques and many Dubai buildings, offices, malls, and airports have dedicated ablution areas.

If you see specially plumbed washing benches near a prayer room, that's what they're for. Renewed whenever it's broken; not a one-time act.